Technical Field
The present disclosure relates to a manufacturing method for a fluid-ejection device and to a fluid-ejection device. In particular, the present disclosure regards a process for manufacturing a fluid-ejection head based upon piezoelectric technology, and to a fluid-ejection head that operates using piezoelectric technology.
Detailed Description
Known to the prior art are multiple types of fluid-ejection devices, in particular ink-jet heads for printing applications. Similar heads, with appropriate modifications, may likewise be used for ejection of fluids other than ink, for example for applications in the biological or biomedical field, for local application of biological material (e.g., DNA) in the manufacture of sensors for biological analyses, for the decoration of fabrics or ceramics, and in applications of 3D printing and additive manufacturing.
Known manufacturing methods envisage coupling via gluing or bonding of a large number of pre-processed parts. This process proves costly and calls for high precision, and the resulting device has a large thickness.
To overcome these drawbacks, the document No. US 2014/0313264 discloses a manufacturing method for a fluid-ejection device completely obtained on a silicon substrate with technologies typical of manufacture of semiconductor devices and formed by coupling together just three wafers. According to this process, however, manufacture of the nozzle is obtained following upon coupling of the wafer bearing the nozzle to the other wafers, already coupled together. The consequence of this is a limited freedom of action on the stack thus formed, in part on account of the machines used for handling a stack of coupled wafers, and in part on account of the technological processes, which are not compatible with the adhesive material used for coupling the three wafers (e.g., high-temperature processes or processes involving use of some types of solvents). Furthermore, formation of an anti-wetting coating around the nozzle proves inconvenient.